Rendering text to a canvas in a frame-less document.

third_party/WebKit/Source/core/css/resolver/StyleResolver.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 2004-2005 Allan Sandfeld Jensen (kde@carewolf.com)
  * Copyright (C) 2006, 2007 Nicholas Shanks (webkit@nickshanks.com)
  * Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013 Apple Inc. All rights reserved.
  * Copyright (C) 2007 Alexey Proskuryakov <ap@webkit.org>
  * Copyright (C) 2007, 2008 Eric Seidel <eric@webkit.org>
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (c) 2011, Code Aurora Forum. All rights reserved.
  * Copyright (C) Research In Motion Limited 2011. All rights reserved.
@@ skipping 693 matching lines @@
 
 // Start loading resources referenced by this style.
 void StyleResolver::loadPendingResources(StyleResolverState& state)
 {
     state.elementStyleResources().loadPendingResources(state.style());
 }
 
 PassRefPtr<ComputedStyle> StyleResolver::styleForElement(Element* element, const ComputedStyle* defaultParent, StyleSharingBehavior sharingBehavior,
     RuleMatchingBehavior matchingBehavior)
 {
-    ASSERT(document().frame());
     ASSERT(document().settings());
     ASSERT(!hasPendingAuthorStyleSheets());
     ASSERT(!m_needCollectFeatures);
 
     // Once an element has a layoutObject, we don't try to destroy it, since otherwise the layoutObject
     // will vanish if a style recalc happens during loading.
     if (sharingBehavior == AllowStyleSharing && !document().isRenderingReady() && !element->layoutObject()) {
         if (!s_styleNotYetAvailable) {
             s_styleNotYetAvailable = ComputedStyle::create().leakRef();
             s_styleNotYetAvailable->setDisplay(NONE);
@@ skipping 1019 matching lines @@
     visitor->trace(m_siblingRuleSet);
     visitor->trace(m_uncommonAttributeRuleSet);
     visitor->trace(m_watchedSelectorsRules);
     visitor->trace(m_treeBoundaryCrossingScopes);
     visitor->trace(m_styleSharingLists);
     visitor->trace(m_pendingStyleSheets);
     visitor->trace(m_document);
 }
 
 } // namespace blink